The article reviews the natural levels of carbon, nitrogen, and phosphorus in world rivers, based on literature data. Natural levels are mainly derived from major rivers in unpolluted subarctic and tropical zones and smaller streams in temperate zones. Atmospheric fallout is also considered. Dissolved organic carbon (DOC) varies from 1 to 20 mg/l, with an average of 5.75 mg/l. Particulate organic carbon (POC) is inversely related to suspended matter, varying from 0.5 to 40% of total suspended matter, with an average of 1%. The DOC/TOC ratio varies from 10 to 90%, decreasing with suspended matter. The average DOC/TOC ratio is likely 0.6, but lower ratios are found in highly erosive environments. Total organic carbon (TOC) transport rates are generally only 1-2% of terrestrial net primary production. Nitrogen forms include dissolved organic nitrogen (DON), dissolved inorganic nitrogen (DIN), and particulate organic nitrogen (PON). Natural levels are low, with DIN at 120 μg/l and DON at 260 μg/l. In subarctic zones, DON represents 60-90% of total dissolved nitrogen, while most river-borne nitrogen is linked to PON. The C/N ratio in river particulate matter is constant, around 8-10. Phosphorus is naturally low, with P-PO₄ at 10 μg/l and total dissolved phosphorus (TDP) at 25 μg/l. Particulate phosphorus represents 95% of river-borne phosphorus, with 40% in organic form. Average nutrient contents in rain are similar to those in unpolluted rivers. River nutrient loads are a minor part of the annual biological cycle, with 1% for carbon, 15% for nitrogen, and 4% for phosphorus. Human activities have increased nutrient levels, with total dissolved P and N increasing by a factor of two globally. River transport of material has been studied for over a century, providing essential information on processes affecting the continental surface and the amount of material carried to water bodies. Previous budgets of N, P, and C were based on crude estimates, but recent studies have provided more detailed data. The article discusses the forms of N, P, and C in natural waters, previous budgets, computation methods, and the origin of basic data. It also examines the natural levels of N, P, and organic C, their relative proportions, and the amount of nutrients carried by rivers compared to precipitation input and plant production. The article concludes with a summary of the findings and the importance of river transport in the global nutrient cycle.The article reviews the natural levels of carbon, nitrogen, and phosphorus in world rivers, based on literature data. Natural levels are mainly derived from major rivers in unpolluted subarctic and tropical zones and smaller streams in temperate zones. Atmospheric fallout is also considered. Dissolved organic carbon (DOC) varies from 1 to 20 mg/l, with an average of 5.75 mg/l. Particulate organic carbon (POC) is inversely related to suspended matter, varying from 0.5 to 40% of total suspended matter, with an average of 1%. The DOC/TOC ratio varies from 10 to 90%, decreasing with suspended matter. The average DOC/TOC ratio is likely 0.6, but lower ratios are found in highly erosive environments. Total organic carbon (TOC) transport rates are generally only 1-2% of terrestrial net primary production. Nitrogen forms include dissolved organic nitrogen (DON), dissolved inorganic nitrogen (DIN), and particulate organic nitrogen (PON). Natural levels are low, with DIN at 120 μg/l and DON at 260 μg/l. In subarctic zones, DON represents 60-90% of total dissolved nitrogen, while most river-borne nitrogen is linked to PON. The C/N ratio in river particulate matter is constant, around 8-10. Phosphorus is naturally low, with P-PO₄ at 10 μg/l and total dissolved phosphorus (TDP) at 25 μg/l. Particulate phosphorus represents 95% of river-borne phosphorus, with 40% in organic form. Average nutrient contents in rain are similar to those in unpolluted rivers. River nutrient loads are a minor part of the annual biological cycle, with 1% for carbon, 15% for nitrogen, and 4% for phosphorus. Human activities have increased nutrient levels, with total dissolved P and N increasing by a factor of two globally. River transport of material has been studied for over a century, providing essential information on processes affecting the continental surface and the amount of material carried to water bodies. Previous budgets of N, P, and C were based on crude estimates, but recent studies have provided more detailed data. The article discusses the forms of N, P, and C in natural waters, previous budgets, computation methods, and the origin of basic data. It also examines the natural levels of N, P, and organic C, their relative proportions, and the amount of nutrients carried by rivers compared to precipitation input and plant production. The article concludes with a summary of the findings and the importance of river transport in the global nutrient cycle.